We've owned Corgi's for what seems like forever and one of the first things we were told was not to leave the collar on the dog when they are not leaded. The reasoning was that because of their short legs they ran the risk of getting tangled and stuck on stuff with the possibility of death.
We have collars and tags but we only use them when camping or travelling. Other than that we use the harness, no tags, when we walk them.
The reason I ask this question is because I see photos on this site with unleaded Corgis wearing collars with tags.
To me, the risks of leaving a collar on outweigh the risks of the dog getting lost. Both mine are chipped.
I have heard of dogs strangling themselves on a collar. Plus if they get lost with a collar, they might get stuck on something and not be able to come when you call them. Your dog might be quite nearby and you might never find it.
Our collars stay attached to the leashes and hang by the door. It's as easy to snap a collar on as to put the leash on; probably easier.
I really like our modified Martingales. They do not wear them indoors. They slip on/off over the head easily.